When it was thought that the hardness and wear resistance of stainless steels might be substantially improved by ion nitriding, many attempts were made to gain that important advantage. It eventually developed, however, that such improvement of mechanical properties was only marginal as a practical matter and, moreover, was at the expense of a substantial measure of stainless steel corrosion resistance. As a consequence, industrial use of ion nitriding has been limited and the special requirements of jet engine builders for stainless steel components of improved performance have gone unmet.